Evolution of the Carlsberg Ridge between 60 and 45 Ma: Ridge propagation, spreading asymmetry, and the Deccan‐Reunion hotspot

Dyment, J.

doi:10.1029/98jb01759

Cited by 81 publications

(52 citation statements)

References 38 publications

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“…Widely observed highly reliable imprints of large scale ridge propagation in the area (Miles and Roest, 1993;Chaubey et al, 1998Chaubey et al, , 2002Dyment, 1998;Miles et al, 1998;Royer et al, 2002) indeed strengthen this inference.…”

Section: Discussionsupporting

confidence: 64%

“…Additional time constraints come from the adjacent Arabian Basin, where the seafloor spreading history is well established (e.g., Chaubey et al, 1998Chaubey et al, , 2002Dyment, 1998;Royer et al, 2002). Fig.…”

Section: Interpretation Of Magnetic Anomalies In the Gop Basinmentioning

confidence: 99%

“…The conjugate Arabian and Eastern Somali basins (Northwestern Indian Ocean) have been formed by seafloor spreading along the Carlsberg Ridge since early Tertiary time; the Laxmi and Laccadive ridges mark the landward boundary of this oceanic crust in the Arabian Basin (McKenzie and Sclater, 1971;Norton and Sclater, 1979;Naini and Talwani, 1982;Schlich, 1982;Bhattacharya et al, 1992;Chaubey et al, 1993Chaubey et al, , 1998Chaubey et al, , 2002Miles and Roest, 1993;Miles et al, 1998;Dyment, 1998;Royer et al, 2002). However, between the Laxmi Ridge and the India-Pakistan continental shelf is a wide region of deep offshore, whose genesis and evolution still remains to be confidently established.…”

Section: Introductionmentioning

confidence: 99%

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Early oceanic opening off Western India–Pakistan margin: The Gop Basin revisited

Yatheesh

Bhattacharya

Dyment

2009

Earth and Planetary Science Letters

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The Deccan Traps, one of the best known examples of rapid flood basalt, are considered as marking of the inception of a mantle plume on the Indian continental lithosphere. Their emplacement may be associated with the continental break-up of India and the Seychelles block and later formation of a new spreading centre, the Carlsberg Ridge, while spreading progressively ceased in the Mascarene Basin. Whether rifting, continental break-up, and seafloor spreading predated or were the consequence of the Deccan Traps emplacement is still a matter of debate. This issue is further complicated by the presence of a continental sliver, the Laxmi Ridge, and large basins lying landward of the Laxmi Ridge, such as the Laxmi and Gop basins, where nature of the crust is still ambiguous. The present study attempts to decipher the tectonic setting and the imprints of plume-ridge interaction in the Gop Basin, where the crust has been interpreted as either volcanics-intruded thinned continental crust or oceanic crust formed by a now extinct spreading centre. Based on interpretation of an updated compilation of marine geophysical data, the present study supports the oceanic nature of the crust underlying the Gop Basin and proposes the Palitana Ridge as the extinct spreading centre in this region. The prominent but short sequence of fairly linear magnetic anomalies in the Gop Basin does not allow a unique identification; it can be reasonably explained either as A31r-A25r (~69.3 -56.4 Ma) or as A29r-A25r (~64.8 -56.4 Ma) sequence. The variations of the spreading rates assumed by both these models suggest that spreading in the Gop Basin significantly slowed around 65 Ma, contemporaneous with the magmatic outburst of the Reunion plume on the adjacent western Indian mainland. Subsequently, the Gop Basin spreading centre was waning whereas a new spreading centre was developing further south, close to the (relatively) southward migrating plume. In this last stage, the Gop Basin spreading centre was associated with an abundant magmatism, probably supplied from the plume region.

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Section: Discussionsupporting

confidence: 64%

Section: Interpretation Of Magnetic Anomalies In the Gop Basinmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Early oceanic opening off Western India–Pakistan margin: The Gop Basin revisited

Yatheesh

Bhattacharya

Dyment

2009

Earth and Planetary Science Letters

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“…Our new geomagnetic timescale over 42 Myr (Table 3, see Electronic Supplement) may therefore help to better identify major anomalies, increase the resolution of seafloor dating, and improve reconstructions of the plate tectonic history of oceanic basins (e.g. [42]). …”

Section: Discussionmentioning

confidence: 99%

Geomagnetic field variations between chrons 33r and 19r (83–41 Ma) from sea-surface magnetic anomaly profiles

Bouligand

Dyment

Gallet

et al. 2006

Earth and Planetary Science Letters

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Sea-surface magnetic profiles exhibit coherent short wavelength "micro-anomalies" (or "tiny wiggles") superimposed to the main anomalies due to reversals. In this study, we investigate the nature and distribution of these tiny wiggles on oceanic crust formed during the ∼42 Myr-long period following the Cretaceous Normal Superchron. To this end, we compute stacks of anomaly profiles from different areas in the Indian and Pacific oceans.Using a simple method based on upward continuation, we demonstrate that, the tiny wiggles are consistent worldwide although their patterns exhibit different resolutions at different spreading rates. They are therefore confidently ascribed to past fluctuations of the geomagnetic dipole moment. A high resolution record of these fluctuations is obtained by selecting and stacking profiles from areas with the highest spreading rates. Modeling the micro-anomalies as short magnetic polarity intervals yields durations for these intervals generally shorter than 10 kyr, likely too short to be indeed "true" subchrons. Moreover, the number of detected tiny wiggles clearly depends on the spreading rate. These results support geomagnetic intensity fluctuations as being the cause of most tiny wiggles, as also Preprint submitted to Elsevier Science suggested by recent magnetostratigraphic data. The tiny wiggles are uniformly distributed within chrons, indicating that paleointensity fluctuations are neither inhibited after, nor enhanced before, a reversal beyond a "blind" zone of about 10 km (corresponding to 80 to 250 kyr depending on the spreading rate) for which the anomalies due to reversals prevent the detection of tiny wiggles. Most tiny wiggles probably represent a filtered record of a uniform secular variation regime, as suggested by their uniform spatial distribution over the whole investigated period.

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“…It has also been observed that ridge segments most influenced by hot- spots commonly elongate ("propagate") at the expense of neighboring segments, resulting in characteristic V-shaped segment discontinuities pointing away from the hotspots (e.g., Phipps Morgan and Sandwell, 1994) (Figure 2 plained by the mixing of "normal" and hotspot mantle materials (e.g., Schilling, 1991 marine gravity and magnetics reconstructing a kinematical history of interacting ridge-hotspot systems (e.g., Dyment, 1998;Müller et al, 1998Müller et al, , 2001). the average crustal thickness of normal mid-ocean ridges (e.g., Darbyshire et al, 2000), while the maximum crustal thickness along the Reykjanes Ridge is twice that of the average values for normal ocean ridges (Weir et al, 2001).…”

Section: Bathymetrymentioning

confidence: 99%

Ridge-Hotspot Interactions: What Mid-Ocean Ridges Tell Us About Deep Earth Processes

2007

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Hawaii (Morgan, 1971). In contrast, the "anti-plume" school argues that many of the observed "hotspot" volcanic and geochemical anomalies are simply due to melts leaking through tensional cracks in Earth's lithospheric plates-in other words, hotspots reflect only where the lithospheric plate is cracked, allowing melts to pass through, and not where the underlying mantle is hotter (see www.mantleplumes.org). A hybrid notion is that only a relatively small number of hotspots, especially those of enormous magmatic volumes, have their origin in buoyant thermal plumes rising from the deep mantle (e.g., Courtillot et al., 2003). Regardless of its specific depth of origin, however, when a hotspot is located close enough to a mid-ocean ridge, the two volcanic systems will interact, resulting in unique volcanic, geochemical, and hydrothermal features. In this paper, we discuss major features of hotspot-ridge interactions.

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Evolution of the Carlsberg Ridge between 60 and 45 Ma: Ridge propagation, spreading asymmetry, and the Deccan‐Reunion hotspot

Cited by 81 publications

References 38 publications

Early oceanic opening off Western India–Pakistan margin: The Gop Basin revisited

Early oceanic opening off Western India–Pakistan margin: The Gop Basin revisited

Geomagnetic field variations between chrons 33r and 19r (83–41 Ma) from sea-surface magnetic anomaly profiles

Ridge-Hotspot Interactions: What Mid-Ocean Ridges Tell Us About Deep Earth Processes

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